virtual lans (vlans) · (collision domains) lan (broadcast domain) hub hub bridge or switch router...

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Feature Overview and Configuration Guide

Virtual LANs (VLANs)

VLAN IntroductionThis guide describes Virtual LANs (VLANs), VLAN features and configuration on the

switch. It begins with a description of what a VLAN is, its evolution and purpose, and also

provides the meaning of some common VLAN terminology.

This is followed with a detailed look at VLAN implementation. Port-based VLAN

membership is the most common way to split a network into sets of virtual LANs. We look

at how this is achieved using the VLAN tagging.

The use of double-tagging (or VLAN stacking) to tunnel VLANs across Layer 2 networks is

described, and an example is provided for the configuration of VLAN stacking.

Next we discuss private VLANs and the communication rules that limit what is possible

between devices operating within the VLAN. AlliedWare Plus™ has three private VLAN

solutions. They are private VLANs for ports in:

Access mode

Trunked mode

Upward Forwarding Only (UFO) mode.

Configuration examples are provided for these solutions.

Then, we look at combining private VLANs with other features, such as: EPSR, ARP, LLDP,

GVRP, Link aggregation, and management servers. The guide ends with a section on

configuring protocol based VLANs and then describes how data counters are used to

count both the number of received frames or the number of received bytes (octets)

belonging to a particular VLAN.

x alliedtelesis.comC613-22001-00 REV D

Products and software version that apply to this guide

This guide mainly applies to all AlliedWare Plus™ products, running version 5.4.4 or later.

However, the private VLAN solution using Upward Forwarding Only (UFO) mode applies to

products running version 5.4.7-1.2 or later.

To see whether a product supports a particular feature or command, see the following

documents:

The AlliedWare Plus Datasheet

The product’s Datasheet

The product’s Command Reference

These documents are available from the above links on our website at alliedtelesis.com.

Feature support may change in later versions. For the latest information, see the above

documents.

| Products and software version that apply to this guide

http://www.alliedtelesis.com/sites/default/files/alliedwareplus_ds_revzd.pdf

http://alliedtelesis.com

http://www.alliedtelesis.com/library?field_document_type_tid=441&combine=

http://www.alliedtelesis.com/library?field_document_type_tid=471&combine=command

ContentsVLAN Introduction...............................................................................................................1

Products and software version that apply to this guide...............................................2

Virtual LANs ........................................................................................................................5

What is a VLAN?...........................................................................................................5

The purpose of VLANs .................................................................................................5

Using routers to segment LANs ...................................................................................6

Using switches to segment LANs ................................................................................6

Domain terminology .....................................................................................................7

Using VLANs to segment LANs....................................................................................7

Implementing VLANs ..........................................................................................................9

Port-based VLANs........................................................................................................9

Distributing a single VLAN across multiple switches ...................................................9

How does tagging work? ...........................................................................................10

Mixing tagged and untagged packets on the same port ...........................................11

Only accepting packets that match the port’s VLAN configuration (ingress filtering) 12

Configuring VLANs .....................................................................................................13

VLAN Double Tagging (VLAN Stacking) ............................................................................15

How double-tagged VLANs work...............................................................................15

VLAN rules for double tagging ...................................................................................17

Configuring double-tagged VLANs ............................................................................17

Private VLANs ...................................................................................................................20

AlliedWare Plus private VLAN solutions .....................................................................21

Private VLANs for Ports in Access Mode .........................................................................22

Membership rules for private VLANs in Access mode ...............................................22

Promiscuous ports .....................................................................................................23

Host ports...................................................................................................................23

Private VLAN operation with ports in Access mode ..................................................24

Access mode private VLAN configuration examples .................................................26

Private VLANs for ports in Trunked Mode.........................................................................28

Port roles in private VLANs for trunked ports.............................................................28

Trunked port private VLAN configuration example.....................................................30

Mixed tagged and untagged private VLANs example................................................33

VLAN translation.........................................................................................................34

Private VLANs for Switchports in Upstream Forwarding Only (UFO) Mode .....................36

Introduction ................................................................................................................36

How is UFO useful?....................................................................................................36

Products and software version that apply to this guide |

UFO features.............................................................................................................. 37

UFO advantages........................................................................................................ 37

How does UFO work?...................................................................................................... 38

Determining upstream and downstream ................................................................... 38

Protection and redundancy ....................................................................................... 38

Limitations ................................................................................................................. 40

How to use UFO............................................................................................................... 41

Configuring the private VLAN .................................................................................... 41

Configuring upstream interfaces ............................................................................... 41

Configuring downstream interfaces........................................................................... 42

UFO Configuration Examples........................................................................................... 43

Monitoring UFO................................................................................................................ 45

Combining Private VLANs with Other Features - Limitations .......................................... 47

Using private VLANs with EPSR................................................................................ 47

Using private VLANs with ARP .................................................................................. 47

Using private VLANs with LLDP ................................................................................ 48

Using private VLANs with GVRP ............................................................................... 48

Using private VLANs with link aggregation................................................................ 48

Using private VLANs with management utility servers .............................................. 48

Protocol-Based VLANS.................................................................................................... 49

Protocol based VLAN configuration example............................................................ 50

VLAN Statistics ................................................................................................................ 52

Counter operation...................................................................................................... 53

| Products and software version that apply to this guide

Virtual LANsA VLAN is a logical, software-defined subnetwork. It allows similar devices on the network

to be grouped together into one broadcast domain, irrespective of their physical position

in the network. Multiple VLANs can be used to group workstations, servers, and other

network equipment connected to the switch, according to similar data and security

requirements.

What is a VLAN?

In simple terms, a VLAN is a set of workstations within a LAN that can communicate with

each other as though they were on a single, isolated LAN. What does it mean to say that

they “communicate with each other as though they were on a single, isolated LAN”?

Among other things, it means that:

broadcast packets sent by one of the workstations will reach all the others in the VLAN.

broadcasts sent by one of the workstations in the VLAN will not reach any workstations

that are not in the VLAN.

broadcasts sent by workstations that are not in the VLAN will never reach workstations

that are in the VLAN.

the workstations can all communicate with each other without needing to go through

a gateway. For example, IP connections would be established by ARPing for the

destination.

IP and sending packets directly to the destination workstation—there would be no

need to send packets to the IP gateway to be forwarded on.

the workstations can communicate with each other using non-routable protocols.

The purpose of VLANs

The basic reason for splitting a network into VLANs is to reduce congestion on a large

LAN. To understand this problem, we need to look briefly at how LANs have developed

over the years. Initially LANs were very flat—all the workstations were connected to a

single piece of coaxial cable, or to sets of chained hubs. In a flat LAN, every packet that

any device puts onto the wire gets sent to every other device on the LAN.

As the number of workstations on the typical LAN grew, they started to become

hopelessly congested; there were just too many collisions, because most of the time

when a workstation tried to send a packet, it would find that the wire was already

occupied by a packet sent by some other device.

What is a VLAN? |

This next section describes the three solutions for this congestion that were developed:

Using routers to segment LANs on page 6

Using switches to segment LANs on page 6

Using VLANs to segment LANs on page 7

Using routers to segment LANs

The early solution to this problem was to segment the network using routers. This would

split the network into a number of smaller LANs. There would be less workstations on

each LAN, and so less congestion.

Of course, routable data being sent between LANs would have to be routed, so the layer 3

addresses would have to be organized so that each LAN had an identifiable set of

addresses that could be routed to—such as an IP subnet or an AppleTalk zone. Non-

routable protocols would have to be bridged, which is not quite so congestion-reducing,

because bridges forward all broadcasts. But, at least for unicast packets, a bridge only

forwards packets if it knows that the destination address is not in the originating LAN.

Using switches to segment LANs

As switches became more available, there was a move from chained hubs to a set of hubs

connected to a switch. A switch only sends traffic to a given port if the traffic has to go to

that port. So switches have the effect of reducing congestion at workstations, by stopping

the workstations from seeing all the traffic from the other ports of the switch.

A simple switched network, though, still needs routers to set the boundaries of where

broadcasts are sent (referred to as “broadcast containment”). So, the typical LAN was set

up as shown below in Figure 1.

Figure 1: Typical VLAN

bridge orswitch

workstation

LAN segments(Collision Domains)

LAN(Broadcast Domain)

hub hub

bridge orswitch

router

hub hub

hub hub

| Using routers to segment LANs

Domain terminology

The above figure introduces the concept of a LAN segment. This is also referred to as a

collision domain, because when a device is trying to send a packet, it can only collide with

packets sent by other devices on the same segment. Each LAN segment consists of all

the devices attached to a single switch port—the switch stops packets from different

ports from colliding with each other.

The LAN itself is referred to as a broadcast domain, because if any device within the LAN

sends out a broadcast packet, it will be transmitted to all devices in that LAN, but not to

devices beyond the LAN.

Using VLANs to segment LANs

As LANs became larger, data rates became faster, and users desired greater flexibility, the

routers in a network started to become a bottleneck. This is because:

routers typically forward data in software, and so are not as fast as switches.

splitting up a LAN using routers meant that a LAN typically corresponded to a particular

physical location. This became limiting when many users had laptops, and wanted to

be able to move between buildings, but still have the same network environment

wherever they plugged in.

Switch vendors started implementing methods for defining “virtual LANs”—sets of switch

ports, usually distributed across multiple switches, that somehow interacted as though

they were in a single isolated LAN. This way, workstations could be separated off into

separate LANs without being physically divided up by routers.

At about the same time, hubs became less popular and have been largely replaced by L2

switches. This has made the whole concept of a collision domain somewhat historical. In

modern networks, a “collision domain” mostly consists of a single device attached to an

L2 switch port, or possibly a PC with something like an IP phone attached to it.

So, the layout of the LAN has become more like this next diagram:

Domain terminology |

Figure 2: Segmented VLAN

Instead of the LANs corresponding to physical areas divided from each other by routers,

there are virtual LANs distributed across the network. For example, all the devices in the

various areas labeled “LAN A” all belong to a single virtual LAN—i.e. a single broadcast

domain.

Advantages of using VLANs:

1. Performance. As mentioned above, routers that forward data in software become a bottleneck as LAN data rates increase. Doing away with the routers removes this bottleneck.

2. Formation of virtual workgroups. Because workstations can be moved from one VLAN to another just by changing the configuration on switches, it is relatively easy to put all the people working together on a particular project all into a single VLAN. They can then more easily share files and resources with each other. To be honest, though, virtual workgroups sound like a good idea in theory, but often do not work well in practice. It turns out that users are usually more interested in accessing company-wide resources (file servers, printers, etc.) than files on each others' PCs.

3. Greater flexibility. If users move their desks, or just move around the place with their laptops, then, if the VLANs are set up the right way, they can plug their PC in at the new location, and still be within the same VLAN. This is much harder when a network is physically divided up by routers.

4. Ease of partitioning off resources. If there are servers or other equipment to which the network administrator wishes to limit access, then they can be put off into their own VLAN. Then users in other VLANs can be given access selectively.

VoIP

switch

switch

switch VLAN B

VLAN C

VLAN A

VLAN A

VoIP

VoIP

VLAN A

VLAN B

| Using VLANs to segment LANs

Implementing VLANs

Port-based VLANs

In the previous section, we simply stated that the network is split up into sets of virtual

LANs. It is one thing to say this, it is quite another thing to understand how this is actually

achieved.

Fundamentally, the act of creating a VLAN on a switch involves defining a set of ports, and

defining the criteria for VLAN membership for workstations connected to those ports. By

far the most common VLAN membership criterium is port-based. With port-based VLANs,

the ports of a switch are simply assigned to VLANs, with no extra criteria.

All devices connected to a given port automatically become members of the VLAN to

which that port was assigned. In effect, this just divides a switch up into a set of

independent sub-switches.

Distributing a single VLAN across multiple switches

The figure "Segmented VLAN" on page 8, is an example of a VLAN-based network. It

shows some of VLAN A connected to one switch, and some more of VLAN A connected

to another switch. You may be asking “Are these both part of the same VLAN A, or

separate VLANs that all happen to be called VLAN A?” The answer is that they are all parts

of the same VLAN—there is a single VLAN A that is spread across two switches.

How is this achieved? How does one switch know that when it receives a broadcast

packet that it associates to VLAN A that it must also forward that broadcast to other

switches?

This can be done in a number of different ways, and in the early days of VLANs, just about

every one of these ways was tried. Some vendors had their switches use a proprietary

protocol to inform each other of their VLAN tables; some vendors used time-divided

multiplexing in which different time slots were allocated to different VLANs; other vendors

used frame tagging. In the end, frame tagging became the accepted standard. As we will

see, in most respects this is a simple and elegant solution. However, it initially had one big

downside: it required a fundamental change to the format of the Ethernet header. This

split the world’s Ethernet devices into those that recognized tagged headers and those

that did not recognize tagged headers. In other words, a lot of Ethernet equipment was

rendered obsolete.

Table 1: Port-based VLAN assignment

PORT VLAN

1 1

2 1

3 2

4 1

Port-based VLANs |

How does tagging work?

Simply, 4 bytes are inserted into the header of an Ethernet packet. This consists of 2 bytes

of Tag Protocol Identifier (TPID) and 2 bytes of Tag Control Information (TCI), as shown in

the diagram below:

Figure 3: Tagged Ethernet packet

TPID is the tag protocol identifier, which indicates that a tag header is following and

contains the user priority, Canonical Format Indicator (CFI), and the VLAN ID.

User Priority is a 3-bit field that allows priority information to be encoded in the frame.

Eight levels of priority are allowed, where zero is the lowest priority and seven is the

highest priority.

The CFI is a 1-bit indicator that is always set to zero for Ethernet switches. CFI is used for

compatibility between Ethernet and Token Ring networks. If a frame received at an

Ethernet port has a CFI set to 1, then that frame should not be bridged to an untagged

port.

Then, the VID field contains the identifier of the VLAN. Actually, it is only the VID field that

is really needed for distributing VLANs across switches—but the IEEE decided that while

they were altering the format of the Ethernet header, they might as well add the User

Priority and CFI too.

Let us see how this tag makes it simple to distribute VLANs across switches.

Consider a broadcast packet arriving at a switch port. By some criterion, the packet is

associated with VLAN 47, i.e. a VLAN with VLAN ID=47. Now, port 17 of this switch is

connected to port 12 of another switch that also has some ports in VLAN 47.

The network administrator needs to configure port 17 of switch 1 and port 12 of switch

2 as “tagged” member ports of VLAN 47. This tells switch 1 to send the broadcast out

port 17 as a tagged packet, with VID=47 in the tag. And it tells switch 2 to accept that

tagged packet and associate it with VLAN 47.

Then, switch 2 will send the packet out all its member ports of VLAN 47, because that

is what it does with broadcasts that it has associated with VLAN 47.

2 bytes2 bytes

TPID TCI

User priority CFI VID

3 bits 1 bit 12 bits

| How does tagging work?

Figure 4: Distribute VLANs across multiple switches

The tag makes it very easy for the second switch to know what to do with the packet,

because the tag marks this packet as belonging to VLAN 47, and switch 2 knows exactly

what it should do with packets that belong to VLAN 47.

So, there really are only two simple rules:

If a port is a tagged member of a VLAN, then any packets sent out that port by that

VLAN must have a tag inserted into the header.

If a tagged packet arrives in at a port, and the port is a tagged member of the VLAN

corresponding to the VID in the packet's tag, then the packet is associated with that

VLAN.

With these two simple rules, it is possible to distribute VLANs across multiple switches.

Mixing tagged and untagged packets on the same port

In the previous section, we discussed using tags to indicate the VLAN membership of

packets that are transferred from one switch over to another. But, it is also possible that

untagged packets will be transported across that link that joins the two switches.

For example, it could be that port 17 of switch 1 is an untagged member of VLAN 56, and

port 12 of switch 2 is an untagged member of VLAN 56. In this case, if switch 1 needed to

transport VLAN 56 packets over to switch 2, it would send them untagged.

When those untagged packets arrived at switch 2, what VLAN would switch 2 decide to

associate these packets with, given that they do not have a tag to indicate their VLAN

membership? Well, in fact, switch 2 would realize that VLAN 56 is the untagged VLAN on

the receiving port, so untagged packets would be deemed to belong to VLAN 56.

Obviously, a port can be an untagged member of only one port-based VLAN, otherwise

there would be uncertainty about what VLAN incoming untagged packets belonged to.

This VLAN is often referred to as the native VLAN of the port.

VLAN 47

port 17 port 121. broadcast packet sent to switch

2. untagged broadcast packet sent out VLAN 47 ports on switch 1

3. packet containing VLAN tag with VID=47 sent between switches

VLAN 47

4. untagged broadcast packet sent out VLAN 47 ports on switch 2

Mixing tagged and untagged packets on the same port |

Often, you might not want to associate a native VLAN with the port that connects a switch

to another switch, so that all packets coming into that port must use a VLAN tag to

indicate their VLAN membership. This stops the switch from accepting any untagged

packets on the port. In AlliedWare Plus, this is achieved by configuring a port to Trunk

mode and not configuring a native VLAN on it. In AlliedWare, it is achieved by setting the

parameter acceptable=vlan on the port, so that the port will only accept VLAN-tagged

packets.

Only accepting packets that match the port’s VLAN configuration (ingress filtering)

Consider a port that is connected to a normal workstation. Normal applications on the

workstation will never send tagged packets, so there is no requirement for the switch port

to accept tagged packets.

But, is there any harm if the port does accept tagged packets if they happen to come

along? Well, the answer is “quite possibly yes”. If the workstation does send tagged

packets, then it is very likely doing so for malicious reasons.

To guard against such maliciousness, most switches provide the ability to configure

ingress filtering. When ingress filtering is applied to a port, packets will only be accepted

into a port if they match the VLAN configuration of that port. So, if the port is an untagged

member of one VLAN, and nothing else, then only untagged packets will be accepted on

the port. If the port is tagged for a set of VLANs, then a tagged packet will be accepted

into the port only if it is tagged with the VID of one of the tagged VLANs configured on the

port.

We highly recommend that you configure ingress filtering on all switch ports, because

there is seldom a good reason for a port to accept packets from VLANs that are not

configured on that port. Under AlliedWare Plus, ingress filtering is enabled on all ports by

default.

The switch passes VLAN status information to the Internet Protocol (IP) module that

indicates whether a VLAN is up or down. This information is used to determine route

availability.

The device supports up to 4094 VLANs (the maximum allowed by the VID field in the

802.1Q tag). On some devices a few of these VLANs may be reserved for management

purposes. When the switch is first powered up (and therefore unconfigured), it creates a

default VLAN with a VID of 1 and an interface name of vlan1. In this initial condition, the

switch attaches all its ports to this default VLAN.

The default VLAN cannot be deleted, and ports can only be removed from it if they also

belong to at least one other VLAN. If all the devices on the physical LAN belong to the

same logical LAN, that is, the same broadcast domain, then the default settings will be

acceptable, and no additional VLAN configuration is required.

| Only accepting packets that match the port’s VLAN configuration (ingress filtering)

Configuring VLANs

Defaults By default, all switch ports are in Access mode, are associated with the default VLAN

(vlan1), and have ingress filtering on. You cannot delete vlan1.

VLAN names When you create a VLAN (using the vlan command), you give it a numerical VLAN

Identifier (VID) - a number from 2 to 4094, which is included in VLAN-tagged Ethernet

frames to and from this VLAN. If tagged frames are transmitted from this VLAN, they will

contain this VID in their tag. You may also give it an arbitrary alphanumeric name

containing a meaningful description, which is not transmitted to other devices.

When referring to a VLAN, some commands require the VLAN to be specified by its VID

while some commands require it to be specified by its interface name: vlan<VID>. In

command output, the VLAN may be referred to by its VID, its interface name (vlan<VID>),

or its VLAN name (the arbitrary alphanumeric string). You can name a VLAN with a string

containing “vlan” and its VLAN Identifier (VID). To avoid confusion, we recommend not

naming it “vlan” followed by any number different from its VID.

Access mode A switch port in Access mode sends untagged Ethernet frames, that is, frames without a

VLAN tag. Each port is associated with one VLAN (the port-based VLAN, by default,

vlan1), and when it receives untagged frames, it associates them with the VID of this

VLAN. You can associate the port with another VLAN (using the switchport access vlan

command). This removes it from the default VLAN.

Use Access mode for any ports connected to devices that do not use VLAN tagging, for

instance PC workstations.

Trunk mode A switch port in Trunk mode is associated with one or more VLANs for which it transmits

VLAN-tagged frames, and for which it identifies incoming tagged frames with these VIDs.

To allow a switch port to distinguish and identify traffic from different VLANs, put it in

Trunk mode (using the switchport mode trunk command), and add the VLANs (using the

switchport trunk allowed vlan command). Use Trunk mode for ports connected to other

switches which send VLAN-tagged traffic from one or more VLANs.

A Trunk mode port may also have a native VLAN (by default vlan1), for which it transmits

untagged frames, and with which it associates incoming untagged frames (using the

switchport trunk native vlan command).

Ports in Trunk mode can be enabled as promiscuous ports for private VLANs (using the

switchport mode private-vlan trunk promiscuous command) and secondary ports for

private VLANs (using the switchport mode private-vlan trunk secondary command).

For more information about promiscuous ports, see "Promiscuous ports" on page 23

Mirror ports A mirror port cannot be associated with a VLAN. If a switch port is configured to be a

mirror port (using the mirror interface command), it is automatically removed from any

VLAN it was associated with.

Configuring VLANs |

VLANs and channel groups

All the ports in a channel group must have the same VLAN configuration: they must

belong to the same VLANs and have the same tagging status, and can only be operated

on as a group.

Table 2: Configuring VLANs

Step 1. Create VLANs

awplus#configure terminal Enter Configuration mode.

awplus(config)#vlan database

Enter VLAN Configuration mode.

awplus(config-vlan)#vlan <vid> [name

<vlan-name>] [state {enable|disable}]

or

vlan <vid-range> [state {enable|disable}]

Create VLANs.

Step 2. Associate switch ports with VLANs

awplus(config-vlan)#interface <port-list>

Enter Interface Configuration mode for the switch ports that will be in Access mode for a particular VLAN.

awplus(config-if)#switchport access vlan

<vlan-id>

Associate switch ports in Access mode with VLANs:Associate the VLAN with these ports in Access mode.Repeat for other VLANs and ports in Access mode.

awplus(config-if)#interface <port-list>

Enter Interface Configuration mode for all the switch ports that will be in Trunk mode for a particular set of VLANs.

awplus(config-if)#switchport mode trunk

[ingress-filter {enable|disable}]

Associate switch ports in Trunk mode with VLANs.Set these switch ports to Trunk mode.

awplus(config-if)#switchport trunk allowed

vlan allor

switchport trunk allowed vlan add <vid-list>

Allow these switch ports to trunk this set of VLANs.

awplus(config-if)#switchport trunk native vlan

{<vid>|none}

By default, a Trunk mode switch port’s native VLAN, the VLAN that the port uses for untagged packet, is VLAN 1. Some control packets are untagged, including MSTP CIST BPDUs.If required, change the native VLAN from the default. The new native VLAN must already be allowed for this switch port.

awplus(config-if)exit# Return to Global Configuration mode.

awplus(config)exit# Return to Privileged Exec mode.

awplus#show vlan {all|brief|

dynamic|static|auto|static-ports<1-4094>}

Confirm VLAN configuration.

| Configuring VLANs

VLAN Double Tagging (VLAN Stacking)Double tagged VLANs are used to overlay a private Layer 2 network over a public Layer 2

network. The feature is also known as Nested VLANs, VLAN stacking, and Q-in-Q. It

provides a method of transporting different clients' traffic across a shared Ethernet infrastructure.

Network service providers often have customers whose VLAN IDs overlap, therefore, a solution is required to control each client's traffic when the traffic from different clients is mixed together within the service providers' infrastructure, (i.e. different customers will allocate the same VIDs to their VLANs). With a nested VLAN configuration, each customer

is given a customer-ID (S-Tag), which is a unique identifier within the service provider

infrastructure. Traffic from individual customers is tagged with the S-Tag and segregated

from other customer’s traffic. The VLAN identification of the customer’s network can be

preserved while the traffic is tunneled through the network service provider’s

infrastructure. You may need a special feature licence to use nested VLANs. See your

Allied Telesis distributor or reseller for more information.

How double-tagged VLANs work

In a nested VLAN environment VLAN tagging exists at two levels:

client tagging (C-tag)

service provider tagging (S-tag)

When nested VLAN functionality is enabled, the service provider assigns to each of its

clients an individual 12 bit customer VID called an S-tag. The S-tag field has an identical

structure to the VLAN tag field.

The switch that performs the double tagging has two sets of specially designated ports:

Customer edge ports —that face the customer networks from which single-tagged

packets are arriving.

Provider ports (or Core ports)— that connect into the service provider infrastructure, on

which double-tagged packets are arriving and leaving.

A customer edge port will always be a member of ONE service provider VLAN. A provider

port can be a member of multiple service provider VLANs. Packets entering the customer

port of the service provider switch are VLAN tagged packets with original VLAN identifiers

(C-tag VIDs) from the customer network. When the packets enter the switch via a

customer edge port, the switch adds an S-tag (outer tag) on top of the C-tag (inner tag). If

the packet was originally untagged, then the S-tag becomes the packets one and only

tag. Within the service provider infrastructure, the C-tag (inner tag) is ignored and bridging

is based on the value of the S-tag. When the S-tag tagged packets exit the service

provider network via a customer edge port of the destination switch, the S-tag (outer tag)

is removed. Therefore, when the packets exit the customer port, the original VLAN tags

are preserved.

How double-tagged VLANs work |

Once the S-tag is removed from the packet, it is forwarded “as is” out of the customer-

edge port. The tagged status of the customer port is ignored on egress.

Nested VLAN operation is shown in the diagram below.

Figure 5: Nested VLAN operation

The Ethertype of the outer tag is configurable and can be set by changing the Tag

Protocol Identifier (TPID). By default, the Ethertype is set to 0x8100.

In summary, the nested VLAN functionality makes use of the tag-in-tag technique. The

inner tag comes from the customer; the outer tag comes from the core (provider) switch.

The frame formats at different stages of nested VLAN operation are shown in Figure 6,

Figure 7, and Figure 8 below.

Figure 6: Original standard Ethernet frame

Figure 7: 802.q VLAN tagged frame (frame entering the customer port)

Figure 8: Nested VLAN frame with double tags (frame exiting the core port)

VLANs 100-200

Customer YSite C

EthernetHeader VID 100 Data

EthernetHeader

CID 20

VID100 Data

Customer port 1.0.24VLAN 40

Service Provider Infrastructure

Core port 1.0.1VLANs 40, 20

Core portVLANs 40, 20

EthernetHeader VID 100 DataEthernet

Header VID 100 Data

EthernetHeader VID 100 Data

Customer portVLAN 20

Customer port 1.0.12VLAN 20

Customer portVLAN 40

VLANs 100-200

Customer YSite D

VLANs 100-200

Customer XSite B

VLANs 100-200

Customer XSite A

EthernetHeader

CID 40

VID100 Data

Destinationaddress

(6 Bytes)

Sourceaddress

(6 Bytes)

Length/Type

(2 Bytes)

Data

(0-1500 Bytes) (4 Bytes)

Framechecksum

Ethertype(TPID)

Tag ControlInformation(VID 12 bits)

(2 Bytes)(2 Bytes)

802.1q VLAN tag

Destinationaddress

(6 Bytes)

Sourceaddress

(6 Bytes)

Length/Type

(2 Bytes)

Data


Framechecksum

Ethertype(TPID)

Tag ControlInformation

(CID 12 bits)

(2 Bytes)(2 Bytes)

Outer tag Inner tag

Ethertype(TPID)

Tag ControlInformation(VID 12 bits)

(2 Bytes)(2 Bytes)

Destinationaddress

(6 Bytes)

Sourceaddress

(6 Bytes)

Length/Type

(2 Bytes)

Data


Framechecksum

| How double-tagged VLANs work

VLAN rules for double tagging

These are the rules for when double-tagged VLANs are created on a:

Switch

a nested VLAN belongs to only one customer and can have multiple customer-edge

ports

a port must be either a customer-edge port or a provider port, but cannot be both

Service provider port

accepts only tagged packets

transmits only tagged packets

can be in many double-tagged VLANs

Customer edge port

accepts both tagged and untagged packets

transmits both tagged and untagged packets

can be a member of only one nested VLAN

Configuring double-tagged VLANs

You need a special feature license to use double-tagged VLANs. Contact your authorized

Allied Telesis distributor or reseller for more information.

To configure a double-tagged VLAN, use the following steps:

1. Create the double-tagged VLAN.

2. Configure ports as members of the double-tagged VLAN.

3. Set the Tag Protocol Identifier (TPID).This is an optional step.

If required, you can change the Tag Protocol Identifier (TPID) from its default (for VLAN stacking) of 0x8100 (specified as Hex notation), with the platform vlan-stacking-tpid command. Note that this command specifies the TPID value that applies to all VLANs used for double-tagged VLANs. You cannot set individual TPID values for different VLANs within a multi double-tagged VLAN network.

4. Set the Maximum Receive Unit (MRU).This is an optional step.

Adding the S-tag can result in frame sizes that exceed the maximum of 1522 bytes. In order to cope with these larger than normal frames, you should increase the MRU size set for ports configured for double-tagged VLANs. Set the MRU size to:

9710 bytes for ports that work at speeds of either 100 Mbps or 100 Mbps

10240 bytes for ports that work at speeds of 1000 Mbps

For more information, see the Command Reference documentation of the mru command

VLAN rules for double tagging |

http://alliedtelesis.com/support/documentation_keyword_command.aspx

http://alliedtelesis.com/support/documentation_keyword_command.aspx

Double-tagged VLAN configuration example

Figure 9: VLAN double tagging

Table 3: Configuration procedure for double-tagged VLAN :

Step 1. Create and enable the service provider VLAN 2 (the VLAN to be used in the outer-tag)

awplus#configure terminal

Enter Global Configuration mode.


Enter VLAN database mode.

awplus(config-vlan)#vlan 2 state enable

Create and enable VLAN 2.

awplus(config-vlan)#exit

Return to Global Configuration mode.

Customer Layer 2Network

Service ProviderLayer 2 Network

Customer Layer 2Network

Switch A

Switch B

port1.0.2

port1.0.3

port1.0.6

port1.0.5

Provider port

Provider port

Customer edgeport

Customer edgeport

VLAN_Double_Tagging

Frame transmission usesC-tag in customer network

S-tag either insertedor stripped from packet

S-tag either insertedor stripped from packet

Frame transmission usesS-tag in service providernetwork

Frame transmission usesC-tag in customer network

| Configuring double-tagged VLANs

Step 2. Configure port 1.0.2 as a provider-port member of VLAN 2



awplus(config)#interface port1.0.2

Select port1.0.2 for configuring.


Set the port to Trunk mode.

awplus(config-if)#switchport trunk allowed vlan

add 2

Add the VLAN to be trunked over the port.

awplus(config-if)#switchport vlan-stacking

provider-port

Enable VLAN stacking and set the port to be a provider port.

Step 3. Set the Maximum Receive Unit (MRU)

awplus(config-if)#mru 10240

Specify the MRU size in bytes.

awplus(config-if)#exit


Step 4. Configure port 1.0.3 as a customer edge port member of VLAN 10




Select port1.0.3 for configuring.

awplus(config-if)#switchport mode access

Set the port to Access mode.

awplus(config-if)#switchport access vlan 2

Associate the port with VLAN 2.

awplus(config-if)#switchport vlan-stacking

customer-edge-port

Enable VLAN stacking and set the port to be a customer edge port.



Table 3: Configuration procedure for double-tagged VLAN (continued):

Configuring double-tagged VLANs |

Private VLANsPrivate VLANs are VLANs with additional rules.These rules limit the communication that is

possible between devices operating within the VLAN. This may be necessary for security

reasons. AlliedWare Plus private VLANs provide the ability to divide a VLAN’s ports into

separate “groups” and to allow communication within any individual group, but not

between groups.

A group can be any number of ports or a single port. Private VLANs combine the network

advantages of conventional VLANs, with an added degree of privacy obtained by limiting

the connectivity between selected ports.

This section provides an introduction to:

Private VLANs for ports in Access mode

Private VLANs for trunked ports

Private VLANs for ports in Upstream Forwarding Mode (UFO)

Private VLAN functionality allows your network administrator greater control over the

information end users may access on the LAN.

On public networks in particular, users can be vulnerable to attack from other users on the

same LAN. In addition, there is typically no real need for these users to be able to

communicate directly to one another. A private VLAN is a sensible solution. It creates a

situation where users are isolated from each other, and are only able to exchange packets

with ports that connect to the upstream network.

Some typical scenarios that would benefit from private VLANs include:

Hotels

Universities, particularly student accommodation

Libraries

Internet cafés

Hospitals

Multi Dwelling Unit Internet access via a shared LAN

An example application of a private VLAN would be a library in which user booths each

have a PC with Internet access. In this situation it would usually be undesirable to allow

communication between these individual PCs. Connecting the PC to ports within a private

isolated VLAN would enable each PC to access the Internet or a library server via a single

connection, whilst preventing access between the PCs in the booths.

Another application might be to use private VLANs to simplify IP address assignment.

Ports can be isolated from each other whilst still belonging to the same subnet.

| Configuring double-tagged VLANs

AlliedWare Plus private VLAN solutions

AlliedWare Plus has three private VLAN solutions:

Private VLANs for ports in Access mode

Private VLANs for ports in Trunked mode

Private VLANs for switchports ports in UFO mode

Access mode Private VLANs for ports in Access mode are based on the industry standard which have

the following features:

Primary and secondary VLANs

Isolated and community ports are used in the secondary VLANs

No trunked ports

Trunked mode Private VLANs for ports in Trunked mode have the following features:

One isolated VLAN

No community ports or VLANs

Both the promiscuous and secondary ports are trunked members of the VLAN

UFO mode Private VLANs for switchports in UFO mode are:

Configured on a per VLAN basis

Can coexist with non-private VLANs

Have member interfaces that are considered as downstream or upstream.

Let us take a look at each of these private VLAN solutions in more depth.

AlliedWare Plus private VLAN solutions |

Private VLANs for Ports in Access ModeThis type of private VLAN is actually a set of associated VLANs. This set consists of one

Primary VLAN, and one or more Secondary VLANs.

Primary VLAN

The Primary VLAN is the main VLAN.

The Secondary VLANs in the associated set use the Primary VLAN to communicate to the

rest of the network. In this way, it functions as the “front” VLAN. The Primary VLAN

contains the promiscuous port, which carries the private VLAN traffic to and from the rest

of the network. The promiscuous port is explained in further detail below.

Secondary VLANs

There are two types of Secondary VLANs:

Community VLAN - Ports within a Community VLAN can communicate with each other,

as well as with the promiscuous port. Within a Community VLAN, the normal Layer2

switching functionality applies - flooding of broadcast, multicast and unknown unicast

packets occurs, just as in a standard VLAN.

Isolated VLAN - The ports in an Isolated VLAN are only allowed to communicate via the

promiscuous port. Note that ports within different Secondary VLANs cannot

communicate with each other.

Membership rules for private VLANs in Access mode

The following membership rules apply when creating and operating private VLANs in

Access mode.

Each private VLAN:

must contain one promiscuous port (or aggregated link)

may contain multiple host ports

can be configured to span switch instances

can only contain promiscuous and host ports

cannot use the default VLAN (vlan1)

a private isolated VLAN can only contain a single promiscuous port

a private community VLAN can contain more than one promiscuous port

A promiscuous port:

is a member of the primary VLAN and all its associated secondary VLANs

cannot be a member of both private and non-private VLANs

| Membership rules for private VLANs in Access mode

A host port:

can be a member of multiple private (community) VLANs, but all these VLANs must

share the same promiscuous port

cannot be a host port in some VLANs and a non-host port in others

cannot be a promiscuous port in another VLAN

Promiscuous ports

A promiscuous port (also known as the uplink port), is the one port that can communicate

with all ports that are members of its associated secondary VLANs. Multiple promiscuous

ports can exist in a primary VLAN, but only if the primary VLAN is only associated with

community VLANS (that is, that there are no isolated VLANs associated with this primary

VLAN).

A promiscuous port is a member of the primary VLAN and all associated secondary

VLANs. Its Port VID is set to the VLAN ID of the primary VLAN.

The switch should always use the promiscuous port to connect to the rest of the network.

To configure a promiscuous port, use the following commands:

awplus# conf tawplus(config)# int port1.0.1awplus(config-if)# switchport mode private-VLAN promiscuous

Host ports

All the ports in the private VLAN, other than the Promiscuous Port(s), are referred to as

host ports. All host ports are members of the Primary VLAN, and of one Secondary

VLANs. The PVID of a host port is the VLAN ID of the Secondary VLAN it belongs to. Host

ports have two levels of connectivity depending on whether they exist in an isolated or a

community VLAN:

1. Host ports within an isolated VLAN

These ports are only allowed to communicate with their VLAN’s promiscuous port, even

though they share their secondary (isolated) VLAN with other hosts. The host ports receive

their data from the promiscuous port via the primary VLAN, and individually transmit their

data to the promiscuous port via their common secondary VLAN.

2. Host ports within a community VLAN

These ports are able to communicate with both the promiscuous port and the other ports

within the community VLAN that they are associated with. They receive their data from the

promiscuous port via the primary VLAN, and transmit their data to both the promiscuous

port and the other host ports (within their community VLAN) via their common secondary

VLAN. However, the only external path from a community VLAN is from its promiscuous

port.

Promiscuous ports |

Private VLAN operation with ports in Access mode

A basic private VLAN operation is shown in the following figure. It comprises a primary

VLAN 20 plus community and isolated VLANS.

Figure 10: Private VLAN

The ports on this switch have the following configuration:

Port 1.0.1 is the promiscuous port and is a member of the primary VLAN 20 and all its

associated secondary VLANs.

Ports 1.0.2 to 1.0.4 are members of the community VLAN 21 and are able to

communicate with both the promiscuous port and all other ports in VLAN 21.

Ports 1.0.10 to 1.0.12 are members of the community VLAN 22 and are able to

communicate with both the promiscuous port and all other ports in VLAN 22.

Ports 1.0.6 to 1.0.8 are members of the isolated VLAN 23. Each of these ports can only

communicate with the promiscuous port.

Table 4: Private VLANs - Port Tagging

PORT MODE UNTAGGED VLAN MEMBERSHIP PVID

1.0.1 Promiscuous 20, 21, 22, 23 20

1.0.2 to 1.0.4 Host 20, 21 21

1.0.10 to 1.0.12 Host 20, 22 22

1.0.6 to 1.0.8 Host 20, 23 23

1.0.5 Not members of the private VLAN -

1.0.9 Not members of the private VLAN -

private_VLAN_1_1

Internet

WEB Server

Ports 1.0.2 to 1.0.4Community VLAN 21

plusPrimary VLAN 20

Ports 1.0.10 to 1.0.12Community VLAN 22

plusPrimary VLAN 20

Ports 1.0.6 to 1.0.8Isolated VLAN 23

plusPrimary VLAN 20

Promiscuous Port 1.0.1

VLANs 20 to 23

| Private VLAN operation with ports in Access mode

Private VLANs operate within a single switch and comprise one primary VLAN plus a

number of secondary VLANS. All data enters the private VLAN ports untagged.

Using the example of Figure 10 on page 24, data enters the switch via the promiscuous

port1.0.1 and is forwarded to the host ports using VLAN 20, the primary VLAN. Data

returning from the host ports to the promiscuous port (and exiting the switch) use the

secondary VLAN associated with its particular host port, VLAN 21, 22, or 23 in the

example.

Thus the data flows into the switch via the primary VLAN and out of the switch via the

secondary VLANs. This situation is not detected outside of the switch, because all its

private ports are untagged. Note however, that data flowing between ports within the

same community VLAN will do so using the VID of the community VLAN.

Portfast on private VLANS

Within private VLANs, we recommend that you place all host ports into spanning-tree

portfast mode and enable BPDU guard. Portfast assumes that because host ports will

also be edge ports, they will have no alternative paths (loops) via other bridges. These

ports are therefore allowed to move directly from the spanning-tree blocking state into the

forwarding state, thus bypassing the intermediate states.

Applying BPDU guard is an extra precaution. This feature disables an edge port if it

receives a BPDU frame, because receiving such a frame would indicate that the port has a

connection to another network bridge.

For more information on BPDU guard and portfast, refer to the following commands in the

CLI reference documentation:

spanning-tree portfast bpdu-guard

spanning-tree portfast (STP)

Configuration restrictions

you cannot configure the default VLAN (vlan1) as a private VLAN.

there can only be one Isolated VLAN associated with the Primary VLAN.

there can be multiple Community VLANs associated with the Primary VLAN.

Private VLAN operation with ports in Access mode |

Access mode private VLAN configuration examples

Table 5: Configuration procedure for Access mode private VLANs

COMMAND DESCRIPTION

Step 1. Create the VLANs





awplus(config-vlan)#vlan 20-23

Create the VLANs.

Step 2. Create the private VLANs and set the type

awplus(config-vlan)#private-vlan 20 primary

Create primary VLAN 20.

awplus(config-vlan)#private-vlan 21

community

Create community VLAN 21.


community

Create community VLAN 22.


isolated

Create isolated VLAN 23.

Step 3. Associate the secondary VLANs with the primary VLAN


association add 21

Associate secondary VLAN 21 with the primary VLAN 20.


association add 22



association add 23


Step 4. Set port 1.0.1 to be the promiscuous port




Enter Interface Configuration mode for port1.0.1.

awplus(config-if)#switchport mode

private-vlan promiscuous

Set the port as a promiscuous ports.

| Access mode private VLAN configuration examples

Step 5. Set the other ports to be host ports



awplus(config)#interface

port1.0.2-1.0.4, port1.0.6

Enter Interface Configuration mode for the ports.


private-vlan host

Set the ports as host ports.

Step 6. On the promiscuous port, map the primary VLAN to each of the secondary VLANs





awplus(config-if)#switchport private-vlan

mapping 20 add 21-23

Associate primary VLAN 20 and the secondary VLANs 21 to 23 to the promiscuous port.

Step 7. Associate the community host ports with the community VLANs



awplus(config)#interface port1.0.2-

1.0.4

Enter Interface Configuration mode for ports 1.0.2 to 1.0.4.

awplus(config-if)#switchport private-vlan

host-association 20 add 21

Associate primary VLAN 20 and secondary VLAN 21 to the host ports.



awplus(config)# interface port1.0.10-1.0.12


awplus(config-if)# switchport private-vlan host- association 20 add 22


Step 8. Associate the isolated host ports with the isolated VLAN 23



Table 5: Configuration procedure for Access mode private VLANs (continued)

COMMAND DESCRIPTION

Access mode private VLAN configuration examples |

Private VLANs for ports in Trunked ModeA private VLAN for trunked ports consists of a single Isolated VLAN. There is no concept

of Primary and Secondary VLANs with this type of private VLAN.

The promiscuous port is in this Isolated VLAN.

Private VLANs for trunked ports do not support Community VLANs.

Both the promiscuous and host ports must be in Trunk mode

Port roles in private VLANs for trunked ports

All of the ports in this type of private VLAN are contained within the same Isolated VLAN.

These private VLANs have just two types of port—the promiscuous port, and host ports.

Promiscuous port

The promiscuous port is the only port in the Isolated VLAN which can send and receive

frames from any other port that is a member of this VLAN.

Command awplus(config-if)# switchport mode private-VLAN trunk promiscuous group <group-id>

Promiscuous ports can contain multiple trunked VLANs, but these VLANs may only be

either isolated, or non-private. AlliedWarePlus does not support Community VLANs for

this port type.

Host ports

Command awplus(config-if)# switchport mode private-VLAN trunk secondary group <group-id>

By default, the switch removes host ports from the default VLAN. You can add the host

port to the default VLAN only if it is an Isolated VLAN, and if it exists on the associated

promiscuous port.

awplus(config)# interface port1.0.6-1.0.8


awplus(config-if)#switchport private-vlan host- association 20 add 23


Table 5: Configuration procedure for Access mode private VLANs (continued)

COMMAND DESCRIPTION

| Port roles in private VLANs for trunked ports

The promiscuous port can be a member of multiple Isolated VLANs.

If a host port is a member of multiple Isolated VLANs, then the host port’s promiscuous

port must be the promiscuous port for all of these Isolated VLANs

A promiscuous port in Trunk mode allows you to combine multiple isolated VLANs on a

single trunk port. A port in Trunk mode enabled as a secondary port with the switchport

mode private-vlan trunk secondary command can combine traffic for multiple isolated

VLANs over a trunk.

A private VLAN group for trunked ports comprises the following components:

a single promiscuous port.

one or more isolated secondary (host) ports: These can only communicate with the

associated promiscuous port.

The following membership rules apply when creating and operating private VLANs for

trunked ports.

A promiscuous trunk port:

must be in Trunk mode.

can be a member of both private VLANs and non-private VLANs.

has a group ID that is solely used to associate the promiscuous port with secondary

ports.

A secondary trunk port:

must be in Trunk mode.

can only be a member of private VLANs.

cannot be a promiscuous port in another VLAN.

has a group ID that is solely used to associate the secondary port with its promiscuous

port.

Port roles in private VLANs for trunked ports |

Trunked port private VLAN configuration example

A basic trunked port private VLAN operation is shown in Figure 11.

Figure 11: Trunked port private VLAN

The ports on Switch A have the following configuration:

Port 1.0.1 is the promiscuous port, and has a group ID of 1.

Port 1.0.2 is a secondary port for isolated private VLANs 10 and 20, and has a group

ID of 1.

Port 1.0.3 is a secondary port for isolated private VLANs 10, 20 and 30, and has a group

ID of 1.

The configuration procedure in the table below shows the steps to configure Switch A.

private_VLANs_2_1

secondary port1.0.2

port1.0.2

port1.0.3

port1.0.4

Servers

vlan 10

vlan 20

vlan 30

promiscuous port1.0.1

Switch A secondary port1.0.3

vlan 10, 20 vlan 10, 20, 30

port1.0.1 port1.0.1

vlan 10, 20, 30

Secondary ports cannot directly communicate

| Trunked port private VLAN configuration example

Table 6: Configuration procedure for Switch A

COMMAND DESCRIPTION






awplus(config-vlan)#vlan 10,20,30

Create the VLANs.

Step 2. Create the private VLANs and set the type

awplus(config-vlan)#private-vlan 10 isolated






Step 3. Set port 1.0.1 to Trunk mode and add the VLANs to be trunked over the port

awplus(config-vlan)#interface port1.0.1



Set the switching characteristics of the port to trunk.


vlan add 10,20,30

Add the VLANs to be trunked over this port.









vlan add 10,20


Trunked port private VLAN configuration example |





Enter Interface Configuration mode for port 1.0.3.




vlan add 10,20,30


Step 6. Set port 1.0.1 to be the promiscuous port




Enter Interface Configuration mode for port 1.0.1.

awplus(config-if)#switchport mode private-vlan

trunk promiscuous group 1

Enable the port in Trunk mode to be promiscuous port for isolated VLANs 10, 20 and 30 with a group ID of 1.

Step 7. Set port 1.0.2 to be a secondary port






trunk secondary group 1

Enable the port in Trunk mode to be a secondary port for isolated VLANs 10 and 20 with a group ID of 1.

Step 8. Set port 1.0.3 to be a secondary port






trunk secondary group 1

Enable the port in Trunk mode to be a secondary port for isolated VLANs 10, 20 and 30 with a group ID of 1.

Table 6: Configuration procedure for Switch A (continued)

COMMAND DESCRIPTION

| Trunked port private VLAN configuration example

Mixed tagged and untagged private VLANs example

A real-world customer scenario has the following requirements:

The switch has one uplink port

All other ports can communicate with the uplink port

None of the non-uplink ports can communicate with any port other than the uplink port

There are four VLANs on the switch: Data (VLAN2), SetTopBoxData(STB) (VLAN3),

Multicast (VLAN4), Management (VLAN1000)

The uplink port is untagged in VLAN1000, and tagged in VLAN2, VLAN3, VLAN4

Ports 1- 10 are untagged in VLAN2 (just PC users connected to those ports)

Ports 11 and 12 are untagged in VLAN100 and tagged in VLAN3 and VLAN4 (connected to STBs)

Ports 13 - 17 are untagged in VLAN100 and tagged in VLAN2, VLAN3, VLAN4

(connected to CPEs)

no spanning-tree rstp enable!vlan database vlan 2-4,1000 state enable private-vlan 2 isolated private-vlan 4 isolated private-vlan 3 isolated private-vlan 1000 isolated!#Ports attached to the individual PCsinterface port1.0.1-1.0.10 switchport mode trunk switchport trunk native vlan 2 switchport mode private-vlan trunk secondary group 1!

[continued on next page...]

Figure 12: Mixed tagged and untagged private VLAN example

The configuration that satisfies these requirements is:

1 3 5 7

2 4 6 8

9 11 13 15R

10 12 14 16R

17 19 21 23R

18 20 22 24R

AT-x210-24GTGigabit Ethernet Switch

15 16 23 24

L/A

2 4 6 8 10 12 14 16R 18 20 22 24R

MODE

L/A

MODE

CONSOLE

RS-232

FAULTSTANDBYRESET

POWER

SELECT

1 3 5 7 9 11 13 15R 17 19 21 23R15

16

23

24

SPEED

DUPLEX

MODE

MODE SPEED / DUPLEX

L/A LINK / ACT

L/A LINK / ACT

SFP

CLASS 1LASER PRODUCT

Port1.0.24Untagged for VLAN1000Tagged for VLAN2Tagged for VLAN3Tagged for VLAN4

Ports 13 - 17Untagged for VLAN1000Tagged for VLAN2Tagged for VLAN3Tagged for VLAN4

Ports 11 and 12Untagged in VLAN1000Tagged in VLAN3Tagged in VLAN4

Ports 1 - 10Untagged in VLAN2

Isolated ports

Uplink port

Mixed tagged and untagged private VLANs example |

#Ports attached to the STBs - management on vlan1000interface port1.0.11-1.0.12 switchport mode trunk switchport trunk allowed vlan add 3,4 switchport trunk native vlan 1000 switchport mode private-vlan trunk secondary group 1!#Ports attachd to the CPEsinterface port1.0.13-1.0.17 switchport mode trunk switchport trunk allowed vlan add 2-4 switchport trunk native vlan 1000 switchport mode private-vlan trunk secondary group 1!#Uplink portinterface port1.0.24 switchport mode trunk switchport trunk allowed vlan add 2-4 switchport trunk native vlan 1000 switchport mode private-vlan trunk promiscuous group 1

VLAN translation

Available on IE300, IE510, x510 Series switches from software version 5.4.6 onwards, and the x510 switch from software version 5.4.7-2.x onwards.

VLAN translation translates a VLAN’s VLAN-ID to another value for use on the wire.

In Metro networks, it is common for the Network Service Provider to give each customer

their own unique VLAN, yet at the customer location, give all the customers the same

VLAN-ID for tagged packets to use on the wire. VLAN-ID translation can be used by the

Service Provider to change the tagged packet's VLAN-ID at the customer location to the

VLAN-ID for tagged packets to use within the NSP's network.

VLAN-ID translation is also useful in Enterprise environments where it can be used to

merge two networks together without manually reconfiguring the VLAN numbering

scheme. This situation can occur if two companies have merged and the same VLAN-ID is

used for two different purposes.

Similarly within a Network Service Provider’s network, Layer 2 networks may need to be

rearranged, and VLAN translations make such rearrangement more convenient.

Examples To configure VLAN translation, use the following commands:

switchport vlan translation

To translate VLAN100 to VLAN200 on port1.0.1, use the commands:

awplus#configure terminalawplus(config)#interface port1.0.1awplus(config-if)#switchport vlan translation vlan 200 vlan 100

| VLAN translation

switchport vlan translation default drop

To drop inbound tagged packets if they do not match a VLAN translation entry, use the

commands:

awplus#configure terminalawplus(config)#interface port1.0.1awplus(config-if)#switchport vlan translation default drop

show interface switchport vlan translation

To display VLAN translation information for port1.0.1 and port1.0.2, use the command:

awplus#show interface switchport vlan translation port1.0.1-port1.0.2

awplus#show interface switchport vlan translation port1.0.1-port1.0.2

Interface: port1.0.1VLAN on Wire VLAN------------- ---------------1649 100default dropInterface: port1.0.2VLAN on Wire VLAN------------- ---------------1650 100default accept

VLAN translation |

Private VLANs for Switchports in Upstream Forwarding Only (UFO) Mode

Introduction

Upstream Forwarding Only (UFO) is a Private VLAN feature. It is configured on individual

VLANs and blocks or isolates traffic at Layer 2. It blocks the forwarding of Ethernet frames

between certain ports of a UFO VLAN while allowing forwarding of others.

All data from ports associated with a UFO VLAN must only be forwarded to the upstream

port, which is why it is called Upstream Forwarding Only.

Each UFO VLAN has isolated and non-isolated ports. Isolated ports are called

downstream ports. Non-isolated ports are called upstream ports.

As such, traffic arriving from downstream ports must be forwarded only to upstream

ports. Traffic arriving from an upstream port is allowed to be forwarded to downstream

ports or to other upstream ports.

How is UFO useful?

Some services need to control connections between the port and upstream device. For

example, in applications such as Triple-Play networks, VLANs are often shared across

subscribers and provide a specific service or set of services. Such VLANs are called

Service VLANs. An Internet Service VLAN that is shared amongst subscribers needs to

block subscribers from sending to other subscribers, while a shared Voice Service VLAN

needs to let subscribers forward voice traffic directly with each other.

Because these two VLANs often have the same port memberships, there is a need to

allow isolated VLANs to co-exist with regular VLANs on the same port(s).

Enabling Private VLAN UFO on the Internet VLAN will provide isolation, while allowing the

Voice VLAN to remain operating as a standard or regular VLAN.

| Introduction

UFO features

Private VLANs for UFO have the following features:

UFO is configured on a per VLAN basis.

UFO VLANs can coexist with regular (non-private) VLANs in any mix on any of the same

or different ports.

Upstream traffic can be statically or dynamically configured based on topology

changes detected by topology protocols.

Multiple upstream UFO VLAN members are allowed at the same time.

You cannot group VLANs (no primary, no secondary).

You cannot designate a port as upstream or downstream at the port level (no

community, no isolated, no promiscuous, no secondary group). Designation is only at

the UFO VLAN port membership level.

A UFO VLAN can have member interfaces that are considered as downstream or

upstream.

The UFO VLAN isolates traffic downstream to downstream.

The UFO VLAN permits traffic downstream to upstream and upstream to downstream.

UFO advantages

UFO removes many of the Private VLAN trunk restrictions, this means that:

Regular VLANs can now coexist with UFO VLANs on the same ports.

VLANs can belong to the different port groups.

Ports don’t all have to be trunk ports.

A UFO VLAN can change its upstream based on topology changes. This allows an

aggregation network to be in rings, mesh, etc. and continue to isolate (i.e. block

forwarding of) downstream edge ports across the aggregation network. This means

that protocols such as EPSR can coexist on Private VLAN ports.

UFO features |

How does UFO work?UFO works on a per VLAN basis and implements forwarding and blocking rules on traffic

based on the VLANs member port designation of upstream or downstream.

The UFO forwarding/blocking rules are simple:

Block forwarding of downstream to downstream member ports.

Allow forwarding of downstream to upstream member ports.

Allow forwarding of upstream to downstream member ports.

Allow forwarding of upstream to upstream member ports.

Determining upstream and downstream

Private VLAN UFO determines the role of the member port as upstream or downstream.

By default, the member port is downstream. So if the member port is not upstream it is

downstream.

The upstream member port is otherwise determined based on static, dynamic, or a mix of

the two configurations:

Protection and redundancy

There are applications where 1:1 redundancy is used in routers or application platforms.

Redundancy in these applications can be at the node or module level within a node.

There are a couple of platform classes to consider:

Interface availability coupled with redundancy.

Interface availability decoupled with redundancy.

STATICALLY DYNAMICALLY

Determining Upstream

A private VLAN UFO can have its member ports configured statically as upstream. All other member interfaces need not be specially configured for downstream, as they are downstream by default.

A private VLAN UFO can have its member ports configured as "candidates" for upstream. Whether the candidates actually become upstream or remain as downstream is based on different applications and protocols such as:■ 1:1 Protection■ STP/MSTP■ EPSR■ G.8032 (not currently supported)

| Determining upstream and downstream

Interface availability coupled with redundancy

Some classes of platform couple their interface availability with the availability of the

nodes (or modules within a node) that are providing the redundancy. This means the

nodes are either the Primary point of processing or they are the Secondary or backup

points of processing, and these designations of Primary and Secondary do not change.

Under normal conditions, the Primary node (or Primary module within a node) is in the

Active state, while the Secondary node (or Secondary module within a node) is in the

Standby state. When the Primary node fails, the Secondary node's processors take over

and become Active.

For platforms classes that tie their interfaces to these roles and states, their interfaces can

also be in the Active or Standby state. That is, when a Primary node (or module) is Active,

then its interfaces are also Active, and the Secondary node (or module) is in Standby then

its interfaces are also in Standby. Similarly, when a Secondary node (or module) becomes

Active, its interfaces also become Active.

For example, consider a Voice over IP (VoIP) Gateway with one Primary module for voice

processing and protocol handling (e.g. MGCP) and one interface connected to it. A

Secondary module provides backup for voice processing and protocol handling, and it

too has one interface connected to it.

The two interfaces are connected together via a Layer 2 network and provide heartbeat

messaging with one another to ensure they are running. Using UFO, the VoIP Gateway is

at the upstream point of a Layer 2 network, so the interface performing the Active role is

considered as upstream, and the interface performing the Standby role is considered as

downstream.

Private VLAN UFO supports this by allowing UFO VLAN member ports to be configured

as Primary or as Secondary. The member ports configured as Primary are always

upstream, as long as one or more of these Primary ports are available for carrying traffic.

Technically for UFO, a member port is considered as available if it is "Link Up" and not

blocked at the port level by protocols such as STP, or at the UFO VLAN level by protocols

such as MSTP.

If at least one Primary member port of the UFO VLAN is available, then the Secondary

member port(s) are downstream.

If all the Primary member ports are not available, then the Secondary member ports

take over as upstream.

When at least one Primary member port becomes available again, the roles switch and

the Primary member port(s) become the upstream once again, causing the Secondary

member ports to change back to downstream.

Protection and redundancy |

Interface availability decoupled with redundancy

Most classes of platforms do not couple their interface availability with the availability of

the nodes (or modules within a node) that are providing the redundancy. A good example

of this is VRRP (Virtual Router Redundancy Protocol) setup. In a VRRP setup, interfaces

do not go "Link Up" or "Link Down" based on which VRRP node is Master.

Typically, in a VRRP setup, you only statically configure UFO member interfaces as

"Primary" interfaces (no "Secondary" is needed) as this will be sufficient for providing

multiple upstream interfaces to the redundant VRRP nodes. The two VRRP nodes can

send VRRP advertisements between each other over the upstream interfaces of a UFO

VLAN, and UFO will forward these packets along.

STP/RSTP/MSTP

Private VLAN UFO can interact with STP/RSTP/MSTP to designate as upstream, the UFO

VLAN member that can reach the Root Bridge. The port that can reach the Root Bridge is

called the Root Port. This allows arbitrary Layer 2 topologies to be constructed and have

all upstream traffic make its way to the STP/RSTP/MSTP Root Bridge and all traffic make

its way downstream from the Root Bridge while blocking forwarding otherwise.

EPSR

Private VLAN UFO can interact with EPSR and designate as upstream, the UFO member

interface that can reach the EPSR Master, assuming the UFO VLAN is one of EPSR's

protected data VLANs. This allows Layer 2 ring topologies to be constructed and have all

upstream traffic make its way to the EPSR Master and all traffic make its way downstream

from the EPSR Master while blocking forwarding otherwise.

G.8032 (future)

In the future, private VLAN UFO can interact with G.8032 in a proprietary way and

designate as upstream, the member interface that can reach a specified G.8032 ring

node, assuming the UFO VLAN is one of G.8032's traffic data VLANs. This will allow Layer

2 ring topologies to be constructed and have all upstream traffic make its way to the

designated G.8032 node and all traffic make its way downstream from the designated

G.8032 node while blocking forwarding otherwise.

Limitations

Private VLAN UFO is limited to 16 VLANs.

Layer 3 Switching is not supported on UFO VLANs on 52-port x310 and x510 Series

switches, or VCStack configurations.

| Limitations

How to use UFO

Configuring the private VLAN

To configure a private VLAN to operate as UFO, use the private-vlan command with the

ufo parameter:

awplus(config-vlan)# private-vlan <vid> {primary |community | isolated |ufo}

Once the VLAN is configured to operate as UFO, its member ports will default to

downstream. If the VLAN has already been configured as another type of private VLAN,

this command will be rejected.

Configuring upstream interfaces

To configure the UFO VLAN member ports for a role other than downstream, use the

following command:

awplus(config-if)# switchport mode private-vlan ufo <vid-list> {primary-upstream | secondary-upstream | stp | epsr | g8032 | ucp }

Where:

Table 7: Parameter descriptions for the switchport mode private-vlan ufo command

PARAMETER DESCRIPTION

<vid-list> A comma-separated list, or a range of VLANs, all of which have previously been configured with the private-vlan setting of ufo.

primary-upstream The primary interface port/LAG that the UFO VLAN will attempt to use as the upstream interface. More than one primary-upstream interface can be configured.

secondary-upstream The interface that the UFO VLAN will revert to use as the upstream port if all the primary-upstream ports are unavailable due to being either operationally down (i.e. Link Down) or blocked from forwarding (e.g. STP). More than one secondary-upstream interface can be configured.

stp STP will determine if the interface plays the role of an STP Root Port for the CIST, or for the MSTI that this UFO VLAN belongs to. If it is, then UFO will designate the interface as an upstream interface member for the UFO VLAN.

epsr If the UFO VLAN is a protected data VLAN in an EPSR instance, and the interface is one of the transit node's interfaces, then the interface will determine if an EPSR Master is reachable from the interface. If it is, then UFO will designate the interface as an upstream interface member for the UFO VLAN. Otherwise it is downstream.

Configuring the private VLAN |

To change the role of the member interface back to downstream (or to ensure it remains

as downstream), use the following command:

awplus(config-if)# no switchport mode private-vlan ufo <vid-list>

Configuring downstream interfaces

There is no particular configuration needed to configure a Private-VLAN UFO member

interface as downstream. All Private-VLAN UFO members are by default downstream.

Note, it is possible for a UFO VLAN to be in a state where all members are downstream.

This leaves the Private VLAN UFO unable to Layer 2 forward traffic. The show command

will highlight this condition if it occurs. In addition, SNMP traps, and if available, facility

alarms will also provide notifications of this condition.

g8032 (Future) In the future, g8032 can be used to determine whether the interface is upstream or downstream. If the UFO VLAN is one of the traffic data VLANs being protected in a G8032/ERP instance and the interface is one of the East or West interfaces, then the interface will determine if the "Hello" G8032 node is reachable from the interface. If it is, then UFO will designate the interface as an upstream interface member for the UFO VLAN. Otherwise the interface is downstream.

ucp (Future) In the future, an Allied Telesis protocol upstream Control Protocol (UCP) will be used to determine whether the interface can reach the upstream UCP beacon generator. If it is, then UFO will designate the interface as an upstream interface member for the UFO VLAN.

Table 7: Parameter descriptions for the switchport mode private-vlan ufo command


| Configuring downstream interfaces

UFO Configuration ExamplesIn this example, three VLANs are configured that belong to the same member ports:

VLAN 10 is an Internet VLAN that needs to operate as UFO.

VLAN 20 is a Voice Service VLAN that needs to operate as a standard VLAN

VLAN 30 is an IPTV Service VLAN that needs to operate as UFO.

The two possible upstream ports are: port1.0.1, port1.0.2, the rest are downstream ports.

Table 8: Example private-vlan UFO configuration

COMMAND DESCRIPTION






awplus(config-vlan)#vlan 10,20,30

Configure VLANs 10, 20, and 30.

awplus(config-vlan)#private-vlan 10 ufo

Configure VLAN 10 as UFO

awplus(config-vlan)#private-vlan 30 ufo

Configure VLAN 30 as UFO


awplus (config)# Step 2. Configure the VLAN member interfaces

awplus(config)#interface port1.0.1, port1.0.2,port1.0.3,

port1.0.4

Configure the port interfaces.


Enter Interface Configuration mode and configure trunking.

awplus(config-if)#switchport trunk allowed vlan add

10,20,30

Add VLANs 10, 20, and 30 to the trunk group.


Configuring downstream interfaces |

Step 3. Configure the primary and secondary-upstream interfaces

awplus(config)interface port1.0.1


private-vlan ufo 10, 30 primary-upstream

Configure port1.0.1 as the primary-upstream interface



private-vlan ufo 10,30 secondary-upstream

Configure port1.0.1 as the secondary-upstream interface.Note:Ports1.0.3 and port1.0.4 are not configured as downstream as they are downstream by default.

COMMAND DESCRIPTION


Monitoring UFO

awplus# show vlan private-vlan ufo {all|<vlan-id>} VLAN INTERFACES CONFIGURED TYPE PROTOCOL MISC.-------------------------------------------------------------------------------<vid> <port|lag> <config> <us |ds> <proto> <miscellaneous>....<vid> <port|lag> <config> <us |ds> <proto> <miscellaneous> <miscellaneous>

Use the following command to show the configuration and status of a private VLAN UFO

based VLAN(s) and their member interfaces:

show vlan private-vlan ufo {all|<vlan-id>}

Where:

Table 9: Parameter descriptions for the show vlan private-vlan ufo command


all | <vlan-id> ‘all’ shows all UFO VLANs. <vlan-id> filters on a specified VLAN.

<vid> The VLAN ID configured for private-vlan UFO.

<port | lag> The port and number, or static LAG ‘sa’ and number or dynamic LAG ‘po’ and number.

<config> This is one of "primary-upstream" or "secondary-upstream" or "epsr" or "stp" or "g8032".

<us | ds> us (upstream) or ds (downstream) specifies that the UFO VLAN on this interface is designated as upstream or downstream respectively. If all the member ports are designated as downstream, then "downstream-fault" will be shown instead of "downstream". The fault will not be displayed if an IP Address is attached to the UFO VLAN.

<proto> The protocol used to determine whether the port is upstream or downstream. The protocol can be one of the following:■ Static - the upstream or downstream designation is static through configuration and can not

change. This is the designation by default.■ UFO - the upstream or downstream designation is being determined by UFO itself. This is

mainly when primary-upstream or secondary-upstream have been configured, and UFO dynamically determines based on Link Up/Down events.

■ EPSR - the EPSR protocol running on this interface for this UFO VLAN is dynamically determining whether the EPSR Master is reachable from this interface and if it is, then the interface is designated as upstream, otherwise its downstream.

■ STP - the STP protocol running on this interface for this UFO VLAN is dynamically determining whether this interface is playing the role of an STP Root for the CIST or MSTI that this UFO VLAN belongs to, and if it is , then the interface is designated as upstream, otherwise its downstream.

■ G8032 - the G.8032 protocol running on this interface for this UFO VLAN is dynamically determining whether the G8032 "Hello" node is reachable from this interface and if it is, then the interface is designated as upstream, otherwise its downstream.

■ UCP (FUTURE) - the upstream Control Protocol (UCP) running on this interface for this UFO VLAN is dynamically determining whether the Primary UCP beacon node or its backup Secondary UCP beacon node are reachable from this interface and if it is, then the interface is designated as upstream, otherwise its downstream.

Configuring downstream interfaces |

Example:

<miscellaneous> This provides miscellaneous or supplemental information:

VLAN INTERFACES CONFIGURED TYPE PROTOCOL MISC.-------------------------------------------------------------------------------100 port1.0.1 primary-upstream upstream UFO -100 port1.0.2 secondary-upstream downstream UFO -100 port1.0.3 - downstream Static -200 port1.0.4 epsr downstream EPSR -200 sa1 epsr upstream EPSR 0030.846e.bac7 200 port1.0.5 - downstream Static -300 port1.0.6 - downstream-fault Static -300 port1.0.7 - downstream-fault Static -300 port1.0.8 - downstream-fault Static -400 Port1.0.9 stp upstream STP 0030.846e.9bf4 400 Port1.0.10 stp downstream STP -400 Port1.0.11 downstream Static -500 Port1.0.12 ucp downstream UCP -500 Port1.0.13 ucp upstream UCP 00c0.2500.05B1-P< 00c0.2500.7889-S500 Port1.0.14 - downstream Static -600 Port1.0.12 g8032 upstream G8032 0029.8432.1098600 Port1.0.13 g8032 downstream G8032 -600 Port1.0.14 - downstream Static -

■ HHHH.HHHH.HHHH is the MAC address of the EPSR Master, STP Root Bridge, or G.8032 "Hello" node if known, otherwise "-".

■ (FUTURE) this will also include the MAC addresses of the UCP Primary Node with the MAC address appended with "-P" and UCP Secondary Node appended with "-S", along with an indicator "<" as to which of the two UCP nodes is the "active" upstream node.

Table 9: Parameter descriptions for the show vlan private-vlan ufo command



Combining Private VLANs with Other Features - LimitationsThere are some limitations when combining the private VLANs feature with other features:

Using private VLANs with EPSR

You cannot have Ethernet Protected Switching Ring (EPSR) configured on the switch at

the same time as private VLANs. Private VLANs allow only one promiscuous port,

whereas EPSR topologies require two interfaces to be part of the EPSR loop. However,

Private-VLAN UFO supports EPSR.

Using private VLANs with ARP

Devices that are connected to an Isolated VLAN’s Host Port cannot use Address

Resolution Protocol (ARP) to find the switch's IP address. All packets that the Host Port

receives are sent directly out via the promiscuous port, without following any of the

normal switching operations. This means that ARP requests received on a Host Port are

sent to the promiscuous port instead of the CPU port, and therefore the CPU does not

process them.

For this reason, you cannot ping a switch through a Host Port or use Simple Network

Management Protocol (SNMP) or Telnet to manage the switch through a host port, unless

static ARPs are added to the devices at both ends of the host port's link.

This functionality protects your network. Devices connected to Isolated VLANs’ host ports

are typically not trusted, and this prevents them from having management access to the

switch.

This functionality also means that, without static ARPs, you can't process Layer 3

switching through a host port, since ARPs are required to resolve the nexthops. Receiving

packets on a host port and Layer 3 switching them to a non-private port on another VLAN

is a solution, however, traffic coming the other way won’t process, as ARPs cannot be

dynamically learned on the host port.

Using private VLANs with EPSR |

Using private VLANs with LLDP

Link Layer Discovery Protocol (LLDP) does not work on trunked interfaces. Any private

VLAN solution trunked interfaces cannot also have LLDP configured.

Using private VLANs with GVRP

Private VLAN trunk ports are not supported for GVRP. Private VLAN trunk ports and GVRP

are mutually exclusive.

Using private VLANs with link aggregation

Once you have created a static channel or LACP, configure this aggregate interface as the

promiscuous port, or even as a secondary host interface. Note that the promiscuous/

secondary port status cannot be applied to the individual ports within the aggregation, it

can only be applied to the aggregation itself. However, Link Aggregators can be upstream

or downstream interfaces for UFO VLANs.

Using private VLANs with management utility servers

SNMP, sFlow, DHCP, SYSLOG and other management servers should not be connected

to isolated ports.

| Using private VLANs with LLDP

Protocol-Based VLANSUp until now, we have been thinking just of port-based VLANs. However, there are other

ways of defining VLAN membership. In this section, we will consider another type of VLAN

- namely the Protocol-Based VLAN.

With this VLAN classification method, different protocol types are assigned to different

VLANs. For example, IP defines one VLAN, IPX defines another VLAN, Netbeui yet

another VLAN, etc.

It is possible that a question will come to your mind at this point, like:

“Isn't a VLAN a set of workstations? How does a protocol specify a workstation? Surely a

given workstation can send out packets using different protocols (often at the same time),

depending on which applications it is running?”

At this point, you may be starting to see that the description of a VLAN as a set of

workstations is a bit of a simplification. So, let us look a bit deeper here and get to a better

understanding of what VLAN membership means.

In fact, a given workstation can belong to multiple VLANs. It could belong to one protocol-

based VLAN when sending IP packets, another protocol-based VLAN when sending IPX

packets, and yet another different port-based VLAN when sending some other protocol.

So, certainly, when analyzing the VLAN setup on a network, it is a mistake to ask “what

VLAN does this workstation belong to?” The more meaningful question to ask is “if a

packet of such-and-such a protocol arrived at port x of the switch, which VLAN would that

packet be associated with?”

It is important to really understand the change of mind-set that has just been introduced

here. When initially learning about VLANs, it is usual to think of VLANs as sets of

workstations. And, in practice, this is often all that a network administrator wants to

achieve.

However, once the VLAN configuration on a switch becomes complex, with multiple

VLANs of different types all configured on the same port, it is no longer possible to really

think about the VLAN from the workstation point of view. It becomes necessary to think of

it from the packet point of view.

Therefore, it really is vital to think of packets being associated to VLANs when trying to

understand VLAN configurations. Any other approach just ends in confusion. The main

point is that, when using protocol-based VLANs, it is data streams that are divided into

VLANs, not necessarily whole workstations.

Using private VLANs with management utility servers |

Protocol based VLAN configuration example

See Table 10 on the next page for the procedure to configure Switch A.

Figure 13: Protocol based VLAN configuration

Switch A has the following configuration to enable protocol based VLAN classification:

VLAN 100 and VLAN 101 created and applied to port1.0.2 and port1.0.3 respectively

IPv4 and IPv6 VLAN classifier rules created and mapped to VLAN 100 and VLAN 101

VLAN classifier group created and mapped to port1.0.1

VLAN 100 and VLAN 101 are trunked over port1.0.2 and port1.0.3 respectively

IPv4 packets received on port1.0.1 go to port1.0.2 VLAN 100

IPv6 packets received on port1.0.1 go to port1.0.3 VLAN 101

The configuration procedure below shows the steps to configure Switch A.

protocol_VLAN_1

IPv6 packetsIPv4 packets

VOIP Server

VLAN 100VLAN101

Switch Aport1.0.1

Internet Server

port1.0.2port1.0.3

Customer Network

IPv4 packets go toport1.0.2 VLAN100

IPv6 packets go toport1.0.3 VLAN101

IPv6 packets IPv4 packets

| Protocol based VLAN configuration example

Table 10: Configuration procedure for Switch A

COMMAND DESCRIPTION

Step 1. Create the VLANs 100 and 101





awplus(config-vlan)#vlan 100,101

Create the VLANs.


Exit VLAN Configuration mode.

Step 2. Create two protocol type based VLAN classifier rules for IPv4 and IPv6 mapped to VLAN 100 and 101

awplus(config)#vlan classifier rule 1 proto

ip encap ethv2 vlan 100

Create a VLAN classifier rule 1 for IPv4 packets on VLAN 100.

awplus(config)#vlan classifier rule 2 proto

ipv6 encap ethv2 vlan 101

Create a VLAN classifier rule 2 for IPv6 packets on VLAN 101.

Step 3. Create a group of VLAN classifier rules and map the defined VLAN classifier rules 1 and 2 to the group

awplus(config)#vlan classifier group 1 add

rule 1

Add VLAN classifier rule 1 to VLAN classifier group 1.

awplus(config)#vlan classifier group 1 add

rule 2

Add VLAN classifier rule 2 to VLAN classifier group 1.

Step 4. Associate the created VLAN classifier group 1 with port1.0.1



awplus(config-if)#vlan classifier activate 1

Associate VLAN classifier group 1 with port1.0.1.


Exit Interface Configuration mode.

Step 5. Add VLAN 100 to be trunked over port1.0.2




Enable switchport trunking on port1.0.2.

Protocol based VLAN configuration example |

VLAN StatisticsThis feature provides a series of data counters each able to count both the number of

received frames or the number of received bytes (octets) belonging to a particular VLAN.

Data frames are counted as they enter the switch ports. By allocating VLANs to each

customer, a service provider could use the VLAN counter output to provide the basis for a

traffic based billing component.

Commands

Use these commands to create a VLAN packet counter instance named vlan2-data, and

apply this to count incoming vlan2 tagged frames on ports 1.0.4 and 1.0.5:

awplus(config)# interface port1.0.4,port1.0.5awplus (config-if)# vlan 2 statistics name vlan2-data

To view the counters, use the following command:

awplus# show vlan statistics [name <instance_name>]


vlan add 100

Add VLAN 100 to be trunked over port1.0.2.



Step 6. Add VLAN 101 to be trunked over port1.0.3




Enable switchport trunking on port1.0.3.


vlan add 101

Add VLAN 101 to be trunked over port1.0.3.



Table 10: Configuration procedure for Switch A (continued)

COMMAND DESCRIPTION

| Protocol based VLAN configuration example

Counter operation

In this section we detail two scenarios: in the first scenario the switch is being used at the

edge of the network; in the second scenario it is directly connected to an edge switch. In

each situation, separate counters are maintained for incoming traffic that is associated

with a particular VLAN across a range of ports. This enables both incoming and outgoing

traffic volumes to be measured.

A port may not be assigned to multiple counter instances so as to count frames (or bytes)

within the same VLAN. The byte count includes frame headers, therefore the byte counter

for a VLAN tagged frame will be 4 bytes longer than for an untagged frame.

Where a VLAN packet counter instance encompasses ports on a stacked member and

the member is removed from the stack, these ports will automatically be removed from

the counter instance. If this process removes all ports within a counter instance, then the

instance will be deleted.

Edge switch scenario

This network is shown in Figure 14 on page 54. The total data count is the upload count

plus the download packet count

Customer A data count

The upload data count for customer A is determined by monitoring the inbound VLAN 10

packets on ports 1.0.2 and 1.0.8 (i.e. packets from Customer A's network). These ports

must be untagged members of VLAN 10. Note that packets traveling between these ports

will be included in the count.

The download data count for customer A is determined by monitoring inbound VLAN 10

packets on ports 1.0.17, 1.0.19, 1.0.21, and 1.0.23 (i.e. packets destined for Customer A's

network from the Internet).

Customer B data count

The upload data count for customer B is determined by monitoring the inbound VLAN 20

packets on port1.0.24 (i.e. packets from Customer B's network). This port must be an

untagged member of VLAN 20.

The download data count for customer B is determined by monitoring inbound VLAN 20

packets on ports 1.0.17, 1.0.19, 1.0.21, and 1.0.23 (i.e. packets destined for Customer B's

network from the Internet).

Counter operation |

Figure 14: Packet Counters - Edge Switch Scenario

Non edge switch scenario

This network is shown in Figure 15 on page 55. The total data count is the upload count

plus the download packet count.

Customer A data count

The upload data count for customer A is determined by monitoring the inbound VLAN 10

packets on ports 1.0.18 and 1.0.20, 1.0.22, and 1.0.24 on switch Y (i.e. the traffic from

customer A’s network).

The download data count for customer A is determined by monitoring inbound VLAN 10

packets on ports 1.0.17, 1.0.19, 1.0.21, and 1.0.23.

Customer B data count

The upload data count for customer B is determined by monitoring the inbound VLAN 20

packets on ports 1.0.18 and 1.0.20, 1.0.22, and 1.0.24 on switch Y (i.e. the traffic from

customer B’s network).

The download data count for customer B is determined by monitoring inbound VLAN 20

packets on ports 1.0.17, 1.0.19, 1.0.21, and 1.0.23.

VLAN_Pkt_Counters-1.eps

1 3 5 7 9 11 13 15 17 19 21R 23R

2 4 6 8 10 12 14 16 18 20 22R 24R

x610-24Ts Layer 3 Gigabit Ethernet Switch

CLASS 1LASER PRODUCT D/C

L/A 1000 LINK / ACTHDX / COLFDX10/100 LINK / ACT

PORT ACTIVITY

L/A

D/C

D/C

L/AL/A

STACK

PRES

MSTR

L/A1

2

SFP

21 22 23 24

1 3 5 7 9 11 13 15 17 19 21R 23R

2 4 6 8 10 12 14 16 18 20 22R 24R

FAULT

RPS

MASTER

PWR

STATUS

21

22

23

24

SFPL/ABUSY

READY

FAULT

SD

RESET

CONSOLE

VLAN Packet Counters (Edge Switch Exam ple)

Ports 1.0.2 and 1.0.8 Port 1.0.24

Customer B VLAN 20Customer A VLAN 10

Port 1.0.17Port 1.0.19Port 1.0.21Port 1.0.23

VLAN 10andVLAN 20

Internet

| Counter operation

Figure 15: VLAN Packet Counters - Non Edge Switch Scenario

VLAN_Pkt_Counters-2.eps

1 3 5 7 9 11 13 15 17 19 21R 23R

2 4 6 8 10 12 14 16 18 20 22R 24R




PORT ACTIVITY

L/A

D/C

D/C

L/AL/A

STACK

PRES

MSTR

L/A1

2

SFP

21 22 23 24

1 3 5 7 9 11 13 15 17 19 21R 23R

2 4 6 8 10 12 14 16 18 20 22R 24R

FAULT

RPS

MASTER

PWR

STATUS

21

22

23

24

SFPL/ABUSY

READY

FAULT

SD

RESET

CONSOLE

1 3 5 7 9 11 13 15 17 19 21R 23R

2 4 6 8 10 12 14 16 18 20 22R 24R




PORT ACTIVITY

L/A

D/C

D/C

L/AL/A

STACK

PRES

MSTR

L/A1

2

SFP

21 22 23 24

1 3 5 7 9 11 13 15 17 19 21R 23R

2 4 6 8 10 12 14 16 18 20 22R 24R

FAULT

RPS

MASTER

PWR

STATUS

21

22

23

24

SFPL/ABUSY

READY

FAULT

SD

RESET

CONSOLE

Ports

1.0.17

1.0.19

1.0.21

1.0.23

Ports

1.0.18

1.0.20

1.0.22

1.0.24

Ports

1.0.17

1.0.19

1.0.21

1.0.23

VLAN Packet Counters(Non Edge Switch Exam ple)

Ports 1.0.2 and 1.0.8 Port 1.0.24

Customer B VLAN 20Customer A VLAN 10

Internet

C613-22001-00 REV D

NETWORK SMARTER

alliedtelesis.com

North America Headquarters | 19800 North Creek Parkway | Suite 100 | Bothell | WA 98011 | USA | T: +1 800 424 4284 | F: +1 425 481 3895

Asia-Pacific Headquarters | 11 Tai Seng Link | Singapore | 534182 | T: +65 6383 3832 | F: +65 6383 3830

EMEA & CSA Operations | Incheonweg 7 | 1437 EK Rozenburg | The Netherlands | T: +31 20 7950020 | F: +31 20 7950021

© 2017 Allied Telesis, Inc. All rights reserved. Information in this document is subject to change without notice. All company names, logos, and product designs that are trademarks or registered trademarks are the property of their respective owners.

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